Camera casing and recycling method therefor

ABSTRACT

A camera casing of the present invention is an integral two-color molded product whose case main body ( 32 ) consists of a transparent rigid resin layer ( 32   a ) and an opaque rigid resin layer ( 32   b ). Essential parts of the camera are exposed through the transparent resin layer ( 32   a ), so the camera may be operated from outside the casing. The casing is collected and melted as a whole without discriminating between the transparent rigid resin and the opaque rigid resin, to be recycled as a material for the opaque resin layer ( 32   b ) when the case main body is newly formed by two-color injection molding.

FIELD OF THE ART

The present invention relates to a camera casing and a recycling methodtherefor.

BACKGROUND ART

Lens-fitted photo film units is a kind of handy economical camera thatis preloaded with photo film before it is brought into the market.Because of their handiness and cheapness, the lens-fitted photo filmunits are widely used by many people. There are a variety of lens-fittedphoto film units for respective photographic purposes and applications.Many types of waterproof lens-fitted photo film units have also beendeveloped, and make it possible to photograph in water. The waterprooflens-fitted photo film unit encases a film unit body in a plasticwaterproof casing that is structured to be watertight, and permits afilm winding operation, a shutter release operation and other operationon the film unit body from outside the waterproof casing.

Since the waterproof casing weights on waterproof properties among all,there are many restrictions on design, so the appearance tends to bemonotone. Efforts for avoiding monotony have conventionally been done byputting a bright colored sheet as an accent around the film unit body,or by providing a paper box of the film unit body with ornamentalprinting, before the film unit body is contained in the waterproofcasing. However, unlike other ordinary types of lens-fitted photo filmunit, it has been difficult to provide a waterproof lens-fitted photofilm unit with a superior prominent design, or with preferable colorsfor users while maintaining the low cost.

To solve this problem, Japanese Laid-open Patent Application Nos.10-3113 and 10-3114 disclose waterproof casings, wherein a coloredelastomer waterproof cover is formed integrally with a transparentplastic case main body by two-color injection molding. The waterproofcover not only provides an appropriate waterproof properties, but alsoimproves the design the waterproof casing by constituting it oftransparent portions and colored portions, and thereby makes thewaterproof lens-fitted photo film unit conspicuous as an article.

Japanese Laid-open Patent Application No. 11-174561 discloses alens-fitted photo film unit that uses a casing formed from a rigidplastic and an elastomer by two-color molding. Japanese Laid-open PatentApplication No. 11-109468 discloses a waterproof lens-fitted photo filmunit whose waterproof casing is formed from a rigid transparent plastic,a rigid opaque plastic and an elastomer by three-color molding.

In recent years, it becomes a common sense that recycling of resourcesis especially important for global environmental protection. As for usedlens-fitted photo film units, since they are to be submitted tophotofinishers for development without the photo film being removed fromthe casing, a system has been developed for recycling most parts of thelens-fitted photo film unit after the photo film is removed.

However, from those casings which are formed integrally from differentresin materials with largely different material structures, like theabove mentioned one consisting of a rigid resin and an elastomer,original materials cannot be recovered. So it is impossible to reusethem for the same articles. Since reusable range of such casings islimited, their unit price as recycled material is very cheap. As aresult, recycling cost of these kinds of casings are expensive.

The present invention is made to solve the above problems, and has anobject to provide a camera casing that is good for recycling, and arecycling method that makes it possible to recycle casings efficientlyat a low cost.

DISCLOSURE OF THE INVENTION

According to the present invention, a casing for a camera that containsthe camera and allows to operate the camera from outside the casing ischaracterized in that the casing consists of transparent portionslocated in front of at least those parts of the camera which need to beexposed to external light and opaque or semi-transparent portionscovering other parts of the camera, and that the transparent portionsand the opaque or semi-transparent portions are formed respectively froma transparent rigid resin and an opaque or semi-transparent rigid resinby two-color injection molding. The transparent rigid resin and theopaque or semi-transparent rigid resin preferably have equal or similarphysical and chemical properties to each other.

Unlike the conventional two-color forming products that consist of arigid resin and an elastomer, the casing formed from two kinds of rigidresins by two-color injection molding makes it possible to reuse thecasing as a material for reproducing the same casing while maintainingthe advantage on design that the casing consists of transparent portionsand bright-colored portions. That is, the casing of the presentinvention can be reproduced as the same product, so it makes it possibleto establish a closed recycling system, and is superior in terms ofrecycling.

According to a recycling method for a camera casing that is formed froma transparent rigid resin and an opaque or semi-transparent rigid resinby two-color injection molding, the casing after collected is meltedwithout distinguishing the transparent rigid resin from the opaque orsemi-transparent rigid resin, to be reproduced as an opaque orsemi-transparent resin, and the reproduced opaque or semi-transparentresin material is used as a material for forming the same casing newlyby two-color injection molding.

It is preferable to add pigments, dyes or a transparent rigid resin tothe reproduced material, for adjusting color density thereof, or add anelastic material to the reproduced material, for increasing theelasticity thereof.

The recycling method of the present invention contributes to savinglabor, time and cost for recycling the casing so much that theefficiency of recycling is improved.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a casing of a waterproof lens-fittedphoto film unit according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view of the casing of the waterprooflens-fitted photo film unit of FIG. 1;

FIG. 3 is an exploded perspective view of a film unit body of thewaterproof casing of FIG. 1; and

FIG. 4 is an explanatory diagram illustrating an example where therecycling method of the present invention is applied to a casing of awaterproof lens-fitted photo film unit.

PREFERRED EMBODIMENTS OF THE INVENTION

The present invention will now be described on the basis of anembodiment applied to a waterproof casing of a waterproof lens-fittedphoto film unit. FIG. 1 is a perspective view illustrating an appearanceof a waterproof lens-fitted photo film unit 2. The waterprooflens-fitted photo film unit 2 consists of a film unit body 3 and awaterproof casing 4 that contains the film unit body 3 in a watertightfashion. A shutter lever 5 for shutter-releasing is mounted on a frontside of the casing 4, and a winding knob 6 for winding up a photofilmstrip after exposure is mounted on a top side of the casing. Aphotographic window 9 made of a transparent plastic is provided on thefront side of the casing 4, for exposing a taking lens 7 and a finderobjective window 8 of the film unit body 3 to outside. A look-in window10 made of the transparent plastic is provided on the top side of thecasing 4.

As shown in FIG. 2, the film unit body 3 used in the waterproof typelens-fitted photo film unit 2 is formed with the taking lens 7, thefinder objective window 8 and an opening 11 for the shutter lever on itsfront side, and has on its top side an opening 12 for the winding knob,and a frame counter window 13 for showing the remaining number of framesavailable for exposure. The frame counter window 13 can be observedthrough the look-in window 10 of the casing 4. As shown in FIG. 3, afinder eyepiece window 14 is provided on a rear side of the film unitbody 3. The film unit body 3 is constituted of a body basic portion 19having a cartridge chamber 17 and a film roll chamber 18 formedintegrally therewith, in which an unused photo film cartridge 16 isloaded; an exposure unit 22 mounted to the front of the body basicportion 19 and having the taking lens 7, a finder optical system 20, ashutter mechanism 21, a film winding stop mechanism, a frame countermechanism and other elements incorporated thereinto; and front and rearcovers 23 and 24 that cover the front and rear sides of the body basicportion 19.

A winding dial 28 is pivotally mounted atop the cartridge chamber 22 ofthe body basic portion 19, and is engaged with a spool 27 of a cartridgeshell 26. On a top side of the winding dial 28 is formed an engaginghole 29, in which the winding knob 6 mounted on the casing 4 is engaged.The engaging hole 29 is exposed through the opening 12 that is formedthrough the front cover 23. It is to be noted that the opening 12 isprovided in the place of a shutter button that is provided in a frontcover of a standard lens-fitted photo film unit. The shutter mechanism21 of the exposure unit 22 is exposed through the shutter lever opening11 that is formed through the front of the front cover 23.

The film unit body 3 substantially has the same configurations as theunit body of the standard lens-fitted photo film unit, except that thefront cover 23 and the winding dial 28 are specific for the waterprooftype.

As shown in FIG. 2, the casing 4 consists of a case main body 3 thatcovers the front, top, bottom and opposite sides of the film unit body3, and a lid member 33 that is mated to the case main body 32 from therear of the film unit body 3 in a watertight fashion. The rear side ofthe case main body 32 forms an opening for accepting the film unit body3, and a ridge 38 is integrally formed around the entire circumferenceof the opening 37.

The case main body 32 consists of a transparent resin layer 32 a formedfrom a transparent rigid resin and an opaque resin layer 32 b formedfrom an opaque rigid resin, which are integrally formed by two-colorinjection molding. The opaque resin layer 32 b is formed to cover theoutside of the transparent resin layer 32 a except the photographicwindow 9 and the look-in window 10, so the transparent resin layer 32 ais exposed in those parts corresponding to the photographic window 9 andthe look-in window 10. Although the transparent resin layer 32 a and theopaque resin layer 32 b are shown separately from each other in FIG. 2,in order to show the configuration of the case main body 32 apparently,the transparent resin layer 32 a and the opaque resin layer 32 b aretightly joined to each other as an integral part by two-color injectionmolding. The transparent resin layer 32 a of the case main body 32 isproduced from a highly transparent new resin material. As an exemplaryof the transparent rigid resin that is used as the material of thetransparent resin layer 32 a, general purpose polystyrene (GPPS) may beused. In that case, it is preferable to use a compound of generalpurpose polystyrene and pigments or dyes or the like, as the opaquerigid resin for use as the material of the opaque resin layer 32 b.Because the transparent resin layer 32 a and the opaque resin layer 32 bare both formed from the general purpose polystyrene that is a rigidresin, it comes to be possible to reproduce the opaque resin layer 32 bfrom a resin material that is obtained by melting the case main body 32after it is used up and collected.

It is possible to form the case main body 32 using a semi-transparentresin layer instead of the opaque resin layer 32 b. In that case, lightpermeable pigments may be added to the general purpose polystyrene, orthe amount of pigments is reduced in comparison with the opaque resinlayer. Combination of the transparent resin and the semi-transparentresin makes it possible to manufacture an attractive casing that keepsup with the latest trend of semi-transparent design.

It is also possible to form the opaque or semi-transparent resin layerfrom high-impact polystyrene (HIPS) that is a resin formed by addingbutadiene as an elastic material to GPPS. Thereby the strength of thecase main body 32 is raised. Since the HIPS cannot be transparent, it isimpossible to use it as the material of the transparent resin layer 32a.

The lid member 33 is formed from a transparent plastic, preferably thesame resin material as the transparent resin layer 32 a. According tothe present embodiment, the lid member 33 is formed from transparentGPPS. According to this configuration, the finder objective window 14 isobservable from outside through the rear casing member 33. The lidmember 33 has a recessed portion 64 formed around the entirecircumference thereof on the front side thereof, so the recessed portion64 is force-fitted on the ridge 38 of the opening 37 of the case mainbody 32. A rubber ring 69 is put in the recessed portion 64, for keepingthe case main body 32 and the lid member 33 watertight.

A pair of engaging legs 67 are provided on the front side of the lidmember 33 in either horizontal side thereof, each engaging leg having anengaging hole 66. These engaging legs 67 are engaged with engaging hooks(not shown) that are formed on inside of side walls of the case mainbody 32. Thereby, the lid member 33 is affixed to the case main body 32.

A cylindrical boss 40 is formed to protrude forward on the front side ofthe case main body 32, for pivotally bearing the shutter lever 5. Insidethe boss 40 is formed a hole 41 that is connected to the inside of thecasing 4, and a shaft 43 formed on the rear side of the shutter lever 5is pivotally inserted in the hole 41 of the boss 40. An O-ring 42 with asmall diameter is put in the hole 41 of the boss 40, for preventingwater and dust and the like from entering inside the casing 4 throughthe hole 41.

After the shaft 43 of the shutter lever 5 is inserted in the hole 41 ofthe boss 40, a release lever 44 is affixed to a tip of the shaft 43.When the film unit body 3 is contained in the case main body 32, therelease lever 44 is inserted in the opening 11 that is formed on thefront of the front cover 23, so the release lever 44 is engaged with theshutter mechanism 21 of the exposure unit 22. Thereby, the shuttermechanism 21 inside the film unit body 3 is activated by operating theshutter lever 5 to swing in a counterclockwise direction in thedrawings. A coiled spring 45 is mounted on the outer periphery of theboss 40. The coiled spring 45 urges the shutter lever 5 in a clockwisedirection in the drawings, to reset the shutter lever 5 to its initialposition at any time.

On the top side of the case main body 32 is formed an upward protrudingcylindrical boss 47, for pivotally bearing the winding knob 6. Insidethe boss 47 is formed a hole 48 that is connected to the inside of thecasing 4, and an O-ring 49 with a large diameter is put in the hole 48of the boss 47, for preventing water and dust and the like from enteringinside the casing 4 through the hole 48.

The winding knob 6 consists of an operating portion 51 of a saucer-likeshape with knurls formed around its outer periphery, and a drive shaft52 formed on the bottom side of the operating portion 51. The driveshaft 52 is inserted in the hole 48 of the boss 47, and is engaged inthe engaging hole 29 of the winding dial 28 through the opening 12 thatis formed through the front cover 23 of the film unit body 3.

Accordingly, rotating the winding knob 6 in the counterclockwisedirection in the drawings causes the winding dial 28 of the film unitbody 3 to rotate in the same direction, thereby winding the exposedphoto filmstrip into the cartridge shell 26. Although it is not shown indetail in the drawings, a claw member is formed on an outer peripheralsurface of the drive shaft 52, and is engaged with an inner wall surfaceof the case main body 32 when the drive shaft 52 is inserted in the hole48 of the boss 47, so the winding knob 6 may not slip out of the casemain body 32.

A claw member 54 is pivotally mounted under the winding knob 6, suchthat the claw member 54 is actuated in cooperation with the winding knob6 being rotated. When the winding knob 6 is rotated in a film windingdirection that is the counterclockwise direction in the drawings, theclaw member 54 clicks into engagement with ratchets formed inside theoperating portion 51 of the winding knob 6. When a rotational force isapplied to the winding knob 6 in the clockwise direction in thedrawings, the claw member 54 is interlocked with the ratchets of theoperating portion 51, thereby to stop the winding knob 6 from rotatingin reverse.

Next, a recycling method of the casing 4 of the above embodiment will bedescribed with reference to FIG. 4.

The casing 4 of the present invention, that is manufactured by two-colorinjection molding, is collected after it is used up, and is meltedwithout separating the transparent resin layer 32 a from the opaqueresin layer 32 b, in order to recycle it as a material of the opaqueresin layer 32 b when a case main body 32 is newly manufactured.

Since the transparent resin layer 32 a and the opaque resin layer 32 bare melted together, the density of the pigments, that is contained inthe opaque resin layer 32 b, is lowered from the original pigmentdensity of the opaque resin layer 32 b by adding the transparent GPPS,that constitutes the transparent resin layer 32 a. So the pigments areadded to make up for the shortage of the pigments while melting thecollected products, so as to correct the pigment density to the originalvalue of the opaque resin layer 32 a.

The opaque resin material obtained from the collected casings 4 isformed in pellets and, thereafter, put as the resin material of theopaque resin layer 32 b in a two-color injection molding machine. As theresin material for forming the transparent resin layer 32 a, a newtransparent GPPS is used at that time. In this way, the case main bodies32 are manufactured as two-color formed products. Separately from thecase main bodies 32, the lid members 33 are formed from the transparentGPPS.

Thereafter, the film unit body 3 is put in the two-color formed casemain body 32, and the lid member 33 is mated, and then the winding knob6 and the shutter lever 5 are mounted, completing the waterproof typelens-fitted photo film unit 2.

The case main body 32 as consisting of the transparent resin layer 32 aand the opaque resin layer 32 b, may be melted to be reproduced as asemi-transparent resin material after the case main body 32 iscollected, in order to reuse it for two-color forming of a casing thatuses a semi-transparent resin layer instead of the opaque resin layer 32b. In that case, pigments or dyes or the transparent resin material isadded in accordance with a desirable density of the semi-transparentresin. Also in a case where the casing formed from the transparent resinlayer and the semi-transparent resin layer by two-color forming ismelted to be recycled as a resin material for a semi-transparent oropaque resin layer, it is necessary to add pigments or dyes inaccordance with a desirable density of the semi-transparent or opaqueresin.

When melting those main case body 32 where the opaque resin layer ismade of high impact polystyrene (HIPS), the density of butadiene rubberis reduced by GPPS that constitutes the transparent resin layer 32 a. Soit is preferable to add butadiene rubber concurrently with pigments, forenforcing the elasticity of the opaque resin layer and thus obtaining asufficient strength of the reproduced case main body.

As the two kinds of rigid resins used for the two-color molding, notonly the above mentioned general purpose polystyrene (GPPS) and highimpact polystyrene (HIPS), but also other resins may preferably be usedinsofar as they are chemically or physically equal or similar to eachother, like they have equal or similar chemical structures, or theirmelting points or relative densities are equal or similar to each other.As examples of those materials, acrylonitrile-styrene resin (AS resin),acrylonitrile-butadiene-styrene resin (ABS resin), polycarbonate (PC)may be referred to.

Industrial Application Field

The present invention is preferably applicable not only to the abovedescribed waterproof casing for the waterproof type lens-fitted photofilm unit, but also equally preferably applicable to casings for thestandard lens-fitted photo film units or those for compact cameras. Thepresent invention is not limited to casings for cameras, but may begenerally applicable to recycling of those casings which are formed fromplastics by two-color injection molding.

What is claimed is:
 1. A casing for a camera that contains the cameraand allows a user to operate the camera from outside the casing, saidcasing comprising a front cover and a rear cover, said front covercomprising: transparent portions located in front of at least thoseparts of the camera which need to be exposed to external light; andnon-transparent portions covering other parts of the camera, wherein thetransparent portions and the non-transparent portions are formedrespectively from a transparent rigid resin and non-transparent rigidresin by two-color injection molding, the transparent rigid resin andthe non-transparent rigid resin differing from one another only withrespect to at least one of a pigment and a dye present in thenon-transparent rigid resin.
 2. A casing for a camera as claimed inclaim 1, characterized in that: the transparent rigid resin and thenon-transparent rigid resin have equal or similar physical and chemicalproperties to each other.
 3. A casing for a camera as claimed in claim 1characterized in that: the casing is a casing for a lens-fitted photofilm unit that is previously loaded with a photo film and is to becollected after use.
 4. The casing of claim 1, wherein the rigid resinis general-purpose polystyrene.
 5. A method of recycling a casing for acamera that consists of transparent portions disposed in front of atleast those parts of the camera which need to be exposed to externallight and opaque or semi-transparent portions covering other parts ofthe camera, wherein the transparent portions and the opaque orsemi-transparent portions are formed respectively from a transparentrigid resin and an opaque or semi-transparent rigid resin by two-colorinjection molding, characterized in that: the casing as collected ismelted without distinguishing the transparent rigid resin from theopaque or semi-transparent rigid resin, to be reproduced as an opaque orsemi-transparent resin; and that the reproduced opaque orsemi-transparent resin material is used as a material for the opaque orsemi-transparent portions when forming the same casing newly bytwo-color injection molding.
 6. A recycling method as claimed in claim5, characterized by adding pigments, dyes or a transparent rigid resinto the